Extremely slow to open/close project

It takes about 5-10 min for me to open a project. I meet all the spec requirements and then some. Once the project finally opens, the performance is great. The same thing happens when I try to close a project, and sometimes i have to do a hard close through task manager as the program appears "stuck". Any thoughts as to why this is happening?

In my project which takes 5-10 mins at the "Opening Project" stage, I have 4 maps and 3 basemaps, as well as a layout that has a map frame for each of them plus about another 30 layout elements.

I suspect that the only way that I will be able to speed it up will be to try and reduce the number of maps.

Originally, I thought layers accessing enterprise geodatabase layers may have been the main issue but even when I switch this to being all local (file geodatabase) subsets of those layers the slow "Opening Project" remains.

A tool which could monitor and report on what takes the time when "Opening Project" would be very useful.

I'm starting to get a feel for ArcMon and it appears that the majority of the time (about 100 seconds each) is going on opening three maps that have their file geodatabase feature classes stored in GDA94 (GCS) being displayed in three MGA Zones (PCS).

I do this so that the same project can be used to support deciding on the fly which of those MGA Zones should be used to display the data (my ArcPy code makes the others invisible) based on where in the map series (cursor of a map index feature class; not in-built Map Series) a particular map sheet is located.

In ArcMap I could have decided the spatial reference of a single data frame as the script runs, but in Pro the map frame is "locked" to a map and it is the map that has the coordinate system rather than the map frame. If there is another way to support this requirement I would be keen to know it.

Project opening performance has been a major focus for us in ArcGIS Pro 2.0.0 development. We've optimized opening performance of individual maps and also performance of larger projects containing multiple maps, layouts, etc. We hope you see the benefits of this work once 2.0.0 is released.